CSE 132 (Spring 2015)
Lab 1: Percenterator meets Mt Evans


In Studio 1, you developed a slider that can control a model that represents percentages, from 0 to 100%. In this lab, you attach three such sliders to control the percent of an image's red, green, and blue components that are copied from one panel to another.

Set up

  1. You are encouraged to work in pairs on labs, but if you want to work on your own, that's fine too.

  2. Start Eclipse: In CEC, click on the Start button and look under "All Programs", "Programming" to start up eclipse. The first time Eclipse starts, it will be slower than usual. You will be asked where you want your workspace to be.
    We recommend using the default location, and checking the box so you won't be asked again.
    After Eclipse starts up, click the 'X' on the "Welcome" tab at the top to close the welcome screen.

  3. Identifying your repository: If necessary, open the subversive tutorial in another window for the instructions on how to use subversion to load your repository in eclipse. If you need help with these instructions, ask a TA or another student to help you along.

    When you get to the point of entering the full and complete location of the repository, copy and paste the line below as the repository's URL:
    After pasting:
    • Change YYYY to your WUSTL key, using lower case letters only. Include all punctuation that is normally part of your WUSTL key.

      If you would normally type in the WUSTL key shown on the left, you need to use the version shown in blue on the right to access your repository. Examples:

      • RonKCytron → ronkcytron
      • ima.StudeNt → ima.student
      • Queen.Mary.4 → queen.mary.4

      Although only you can access your repository, you should generally keep your WUSTL key a secret.

    • OK, click Finish to get the repository location validated.
    • When you are prompted for a username and password, supply your
      • WUSTL key username (again, all letters must be lower-case)
      • WUSTL key password
      Your WUSTL key username and password are what you use to log into WebSTAC for registration.

      Be careful! If you provide a bad password repeatedly, your account will get locked out after a small number of such attempts. So be sure to follow these instructions carefully and ask if things are not working.

  4. Continue following the rest of the instructions in the subversive tutorial so that you are back in the Java view and have the project available for your use.
    Those instructions next ask you to Check Out a copy of the repository location so you can do the work for this lab. Be sure to right click on the whole project (your WUSTL key name) to do the checkout. Do NOT click on things below that like src.

  5. As always:
    We push code to your repository throughout the semester. So before you go further, make sure your repo is up-to-date by:
    • Right (control) click on the topmost part of your repository in the package explorer.
    • Drag down to Team
    • Choose Update
  6. Your lab code is found in the labs source folder in the lab1 package.
  7. Open RGB.java in your lab1 package.
  8. You should see a copy of the percent package, similar to what you developed in studio.
  9. This RGB code won't compile until you initialize the green and blue instance variables. Each needs to be an instance of Controller, and each should be added to the RGB (as was done with red).
  10. Run the RGB as a Java application, and use the sliders to change the colors. You can move the sliders as you wish, and when you want to see the resulting picture, click the "go" button.
Unnecessary detail, so skip if you want: Ok you're reading this, so you have a craving for details. I thought that might be the case.

Actually, anytime you stop by you can have the candy.

Pick one of the following

Do two of them in your lab session by the time you demo to earn 10 extra lab credit points and the admiration of your TAs.
In whatever you pick, keep in mind:


When you done with this studio, you must be cleared by the TA to receive credit.

Items Completed
(TA Verify!):
1 item (full credit).
2 items (+10 points extra credit and admiration).
All 3 items (+10 points and true bragging rights!).
Sorry, no more points than 2 items.
Last name WUSTL Key Propagate?
(or your numeric ID) Do not propagate
e.g. Smith j.smith
1 Copy from 1 to all others
2 Copy from 2 to all others

TA: Make sure they commit their code before you sign them out!

TA: Password:

Last modified 15:44:11 CST 21 January 2015 by Ron K. Cytron